The invention relates generally to packaging systems for refrigerated leavened compositions. More specifically, the invention relates to packaging for refrigerated leavened doughs and batters and methods for determining the seal strength necessary to maintain an internal equilibrium pressure necessary to provide a product, resulting from cooking the leavened composition, having a desired specific volume.
Packaging serves any number of functions in the food product industry. Packaging may provide for distribution, promotion, and advertising of the product. Further, packaging can provide for definition of product shape and format, and provides the end consumer with varying degrees of portion control. Packaging may also serve to ensure product purity, quality and overall product integrity up to the point of use. To this end, packaging may also affect certain product characteristics, especially in those products which comprise chemical agents intended to affect product characteristics during or after baking.
The art of packaging food is well developed. For example, Lorber, U.S. Pat. No. 1,861,124, discloses a package for uncooked biscuits having a telescoping cover which rises as the dough rises to provide space for the increase in the size of the dough mass. Vents are provided for air to escape during the rising of the dough. The package may be in the form of a square box with partitions which divide the body of the package into square compartments, or in the form of a tube.
Traller, U.S. Pat. No. 1,988,058, discloses a dough package comprising a roll including sheets of dough between sheets of non-adhesive paper which is rolled into a substantially solid cylindrical mass. Farrar et al., U.S. Pat. No. 4,769,245, disclose a method for packaging brown and serve baked goods. Hot loaves of bread are heat sealed within a film which has horizontal and vertical seams. A minute filter hole or aperture is formed on the bottom of the package which permits the package to breathe without admitting an excess of microbes.
Wiggins, U.S. Pat. No. 3,512,632, discloses a pressure release valve for flexible pouches. Although in this case the food to be packaged is coffee beans, the package here permits venting of carbon dioxide emitted from the coffee beans. The package comprises a pouch or bag constructed of flexible film or sheet fitted with a one-way release valve.
Joslin, U.S. Pat. No. 2,810,650, may be of interest for disclosing doughs and batters which can be stored under refrigerated conditions for a long period of time without excessive gas evolution. Byrd, U.S. Pat. No. 3,502,487, discloses the packaging of foods. The disclosed package is vented for the exhaust of vapors and/or fluids. The package is sealed to prevent re-entry of vapors and/or fluids. The package is intended to accommodate extreme temperature changes and/or pressure conditions.
Drummond et al., U.S. Pat. No. 5,366,744, is directed to a method for making a packaged dough suitable for extended refrigerated storage and to a packaging system for storage of the refrigerated dough. In the packaging system for storage of refrigerated, leavened dough, Drummond teaches the use of a rigid hermetically sealed package containing a dough.
Turpin, U.S. Pat. No. 3,851,757, a two compartment package is described which consists of an outer spirally wound fiber can containing a dough product. The disclosed can also contains a second compartment which holds icing.
Davis, Jr., U.S. Pat. No. 4,038,428, relates to a method of packaging prepared piecrust dough that may be required to remain within its package for relatively long periods of time and within which thereafter the dough may be rolled into piecrust form while still in its packaging receptacle. Thomas, Jr., U.S. Pat. Nos. 5,164,208, and 5,240,133 disclose that engages a lid to a container by the formation of interlocking waves of lid material and container material.
One accepted means of packaging refrigerated, leavened doughs is through the use of fiber board cans such as those disclosed in McDilda et al U.S. Pat. No. 5,084,284. With this type of packaging, the dough is placed in the can prior to substantial proofing, so most of the proofing occurs in the can. The can itself is closed but not hermetically sealed after the dough has been placed in it. The leavening action in the dough causes the dough to rise in the closed can, and as the head space gas vents out of the can, the dough completely fills the inside of the can and seals it.
While many of these systems provide workable packaging alternatives, a large number of variables need to be considered when packaging a leavened composition.
As a result, there is a need in the marketplace for packaging technology which provides an alternative to the technology presently available.
In accordance with one aspect of the invention, there is provided a packaging system for refrigerated doughs or batters. The packaging system is designed to sustain pressure within the interior of the package and still be easily opened by the end consumer. The package of this system is capable of sustaining pressure within the package interior during the entire refrigerated storage life of the product. The package is also easily opened by the end consumer without the need for cutting or otherwise using a tool or additional instrument to open the package such as, for example, peeling the package apart or using other easily opened package configurations. The packaging system is designed to have a pressure holding capacity which is defined as the product of a package dimension subject to internal pressure and an internal equilibrium pressure. The internal equilibrium pressure is determined by the desired final cooked or baked product specific volume. The package dimension subject to internal pressure is determined by the particular package geometry which is, in turn, determined by the product geometry desired. By selecting a desired finished product specific volume, the internal equilibrium pressure necessary to obtain that finished product specific volume can be determined. The internal equilibrium pressure desired and the particular package geometry selected, considered with the ability of the end consumer to easily open the package, ultimately determine the required seal strength for the packaging system.
In accordance with another aspect of the invention, there is provided a method for determining package seal strength for a refrigerated leavened composition. The method comprises determining the specific volume required for the refrigerated leavened composition after baking, determining the internal equilibrium pressure required to attain the specific volume after baking, determining the package dimension subject to the internal equilibrium pressure, and defining the package seal strength by taking the product of the internal equilibrium pressure and the package dimension subject to the internal equilibrium pressure.
The package dimension subject to the internal equilibrium pressure is a projected area which is essentially in a plane of the packaging in which the position of maximum load of the seal lies, the projected area being defined by the portion of this plane which is limited by the inner surface of the package.
In accordance with another aspect of the invention, there is provided a package for leavened dough composition, said package having a seal strength determined by the method of the invention.
By selecting a desired finished product specific volume, and suitable dough product geometries, seal strengths can be predicted that sustain sufficient pressures during storage that provide the desired specific volumes upon cooking or baking the product. The invention provides a system for maintaining pressure within a refrigerated dough product by use of a sealed container. During storage, the leavening agent or agents within the dough generate an amount of gas within the dough. The container is designed to sustain the pressure, resulting from the gas generated by the leavening reaction in the dough, such that the dough product, once baked, attains the desired specific volume. Specific volume of the baked product is one means of gauging final baked product quality. Specific volume of a product is the volume of the product divided by the weight of that same product.
The amount of headspace or free space surrounding the dough in the container is not critical, as long as the container is capable of sustaining the internal equilibrium pressure required to maintain sufficient gas within the dough. Rather, the invention provides a method for ascertaining any number of parameters and defining a packaging system for use with a given dough.
Previously, only a few suitable alternatives to packaging refrigerated dough or batter containing leavening have been available. These packaging systems involve the use of a sturdy fiberboard can capable of sustaining very high levels of pressure within the can. These cans rely on the strength of the fiberboard walls and the crimped metal ends of the can to sustain the pressure within the package environment. Prior to the present invention, however, there have not been suitable alternatives to the fiberboard cans for packaging refrigerated dough which can sustain the dough so that it will result in baked or cooked product having desirable specific volumes. The packaging systems of the present invention permit the use of a much wider variety of packaging materials and configurations, in addition to providing consumer portion control and numerous product configurations desired by the end consumer. Another advantage is that the dough can still be packed prior to significant proofing, so that most of the handling occurs prior to the development of delicate dough structure.
The packaging system of the present invention provides packaging which is easy to open and yet will maintain the internal equilibrium pressure developed in the package during storage. In fact, the package may provide peel strengths of at most about 8 lbs/in which are peelable by the end consumer while having the capability of preserving internal equilibrium pressure under refrigerated conditions for about 6 months or longer.
One important aspect of the invention is that the package head space may be manipulated to provide any number of effects. The package may have any amount of headspace or may be devoid of head space. The packaging system of the invention allows for the partial or complete venting of the head space within the container after sealing. Further, the head space may be partially or fully evacuated and flushed with a fluid material such as a gas after sealing. The packaging system also allows for the containment of an internal equilibrium in the package between the gas contained in the dough and that gas in the head space of the package.
These advantages ultimately permit the use of virtually any kind of sealed container to package the dough, as long as it can sustain the pressure within the container over the storage time. To determine whether a container will sustain sufficient pressure within the dough to result in a desired specific volume, the present technology defines a correlation between dough geometry and seal strength that predicts the packaging requirements.
The compositions that can be used with the present technology are any dough or batter formulations which can generate gas within the composition once sealed in the container. Chemically leavened and yeast leavened doughs are suitable for use with this technology.